A double-diffused-drain (DDD) is often used as a source or drain in a high-voltage (HV) metal-oxide-semiconductor field effect transistor (MOSFET) that is widely used for numerous power device applications. The DDD structure provides a high breakdown voltage for a HVMOSFET and prevents electrostatic discharge that may result in the destruction of a semiconductor device. A DDDMOS device is a typical power device to sustain the higher operating voltage, for example 10V-20V operating voltage. Hot-electron (HC) induced degradation is known as a serious reliability problem for the DDDMOS device. In a conventional DDDMOS device employing insulator spacers (e.g., silicon oxide or silicon nitride) on sidewalls of a polysilicon gate electrode, the HC effect causes serious degradation in transconductance (Gm) and saturation drain current (Idsat). This is increasingly considered to be the most important limiting factor in scaling n-channel MOS transistors because of the higher channel electric field and electron impact ionization rate in micron and submicron n-channel devices.